x86: Use RCU in all users of __module_address().

__module_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_address() with
RCU.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-23-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index 8418a892d195a99ff9dfb5473c3d5afbded5b221..251b65f2ab2168bdd14984222e445f4d856fd094 100644 (file)
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -98,11 +98,10 @@ static inline bool within_module_coretext(void *addr)
 #ifdef CONFIG_MODULES
        struct module *mod;
 
-       preempt_disable();
+       guard(rcu)();
        mod = __module_address((unsigned long)addr);
        if (mod && within_module_core((unsigned long)addr, mod))
                ret = true;
-       preempt_enable();
 #endif
        return ret;
 }

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index d4705a348a80451c3abb309985784e8efab0999a..977ee75e047c844b6f30412234e40d6bc37e94c2 100644 (file)
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -476,7 +476,7 @@ bool unwind_next_frame(struct unwind_state *state)
                return false;
 
        /* Don't let modules unload while we're reading their ORC data. */
-       preempt_disable();
+       guard(rcu)();
 
        /* End-of-stack check for user tasks: */
        if (state->regs && user_mode(state->regs))
@@ -669,14 +669,12 @@ bool unwind_next_frame(struct unwind_state *state)
                goto err;
        }
 
-       preempt_enable();
        return true;
 
 err:
        state->error = true;
 
 the_end:
-       preempt_enable();
        state->stack_info.type = STACK_TYPE_UNKNOWN;
        return false;
 }